Vastu Vihar — registration of booked jayanti apartment located at vastu vihar project 4, chira chas, bokaro

My father has booked a jayanti apartment in vastu vihar project 4 situated at chira chas one year ago but till date no registration has been done though we have paid the registration amount long back ago. Now the concerned person is not responding to our phone call properly and even escaping from picking up the calls. They are just avoiding to do the registration.